Today, various bioactive substances are used in agricultural, medical or other fields, and however, since they are usually employed in larger quantities because of their poor migration to the target, short retention time and easy scattering in air coming from their characteristic properties such as hydrophilic properties hydrophobic properties volatility and the like, fears are always entertained for the safety of such materials, e.g. soil contamination in case of agricultural chemicals, undesired side-effects in case of medicines and the like.
Attempts, therefore, have been made to make a high polymer carrying a bioactive substance, from which the said bioactive substance is released at a controlled rate, thereby attaining the desired effect for a long period of time and obviating the useless, excessive release of the active substance (see, for example, Japanese Patent Application Kokai No. 143326/82).
However, in these attempts, the carrying of bioactive substance on the high polymer was relied on a covalent bond, and therefore, for the release of such substance, hydrolysis under a high temperature and a highly acidic or basic atmosphere had always been required, as well as a long reaction time. Since the hydrolysis rate is very low under mild conditions as in human body, soil, sea water and the like and the desired slow releasing at a controlled rate is hardly obtainable with these products, they have never been put to practical use up to the present time.
An object of the present invention is, therefore, to provide a resin carrying a bioactive substance, from which the said substance is gradually released at a controlled rate through hydrolysis under mild conditions. An additional object of the invention is to provide a resinous composition containing said resin.